This invention presents a way to stabilize and support a structure, such as a passenger compartment in a moving vehicle, so that the supported or secondary structure remains level and stable and mostly free of primary or parent structure undesirable motions. For Example, if the parent structure is a boat hull a secondary structure in the form of a passenger cabin can be made mostly free of vibration and pitch, roll, and yaw motions associated with the boat hull while the boat is either at rest or under way. The instant invention can be applied to stationary applications and to all manner of vehicles, including boats, trains, aircraft, and the like.
There have been attempts to stabilize entire vehicles with a prime example being gyrostabilizers used on boats and ships. The action of a gyrostabilizer is based on the elementary principal of a gyroscope whereby movement of the vessel is resisted by the precessional forces of the gyroscope. The basic fixed position gyrostabilizer can be classified as a passive or responsive system. A refinement of this is the Sperry Gyrostabilizer whereby a small pilot gyroscope is used to actuate the primary, or ship motion resisting, gyroscope so as to cause the primary gyroscope to precess in a direction opposite to that which would result from rolling or other motions of the ship. This is referred to as an active gyrostabilizer. These systems have been installed in large ships and an application in a 40,000 ton ship of a system with three active gyrostabilizers with rotors 13 feet in diameter has been successfully made. The aggregate weight of the three gyrostabilizers when installed was 690 tons or about 1.72 percent of ship displacement. Hull roll reduction accomplished by this installation was about 60 percent while roll reduction of as much 80 percent has been demonstrated on smaller vessels. Gyrostabilizers are described on page 253 of "Modern Ship Design", Second Edition, by Thomas C. Gillmer, Published by Naval Institute Press, Annapolis, Md., 1977. They are also described in the section 3.14 Gyroscopic Stabilizers that is presented on pages 687-689 of "Principals of Naval Architecture" (PNA), Fourth reprinting August, 1977, Edited by John P. Comstock, Published by The Society of Naval Architects and Marine Engineers, 74 Trinity Place, New York, N.Y. 10006. It is to be noted that, on page 689, PNA states, "The principal drawbacks for commercial installations are their cost, weight and size, the space they require, and the power they consume." The instant invention solves the just mentioned deficiency since only the supported structure requires gyroscopic stabilization. This is described in more detail, by way of example, in a following paragraph in this section.
The instant invention actually floats or supports the secondary structure with lifting force supplied by a pressurized gas, normally air, cushion in its preferred embodiment. This offers tremendous benefits since a passenger cabin, for example, can be supported and isolated from parent vehicle movements. There have been successful applications of lifting air cushions applied to primary vehicles, for example Hovercraft and my Air Ride Boat inventions. These air cushion supported vehicles are very efficient; however, they still subject passengers and other cargo to vehicle movements since the passenger cabins are affixed directly to the primary vehicle. Even the use of springs and/or shock absorbers, as are used in automobile suspension systems and some marine and other vehicles, are not truly effective in isolating primary vehicle movement and vibration from the supported structure and its contents. Further, spring mounted systems or the like still allow the supported structure to vibrate and roll, pitch, and yaw in accord with primary vehicle movements only at a slightly reduced or dampened rate. Importantly, the previous supporting systems rely on springs, pneumatic or hydraulic actuators, shock absorbers or other similar means to both carry the full weight of and stabilize the supported structure.
Since the preferred version of the instant invention separates the secondary structure from the parent structure and supports the secondary structure with pressurized gas, the loads on connectors such as springs, pneumatic or hydraulic actuators, shock absorbers or other means is reduced many fold; therefore, the size and power requirements, where required, for these connectors is reduced tremendously also. Further, in the preferred version of the instant invention, connectors may only restrain, which is a form of stabilizing and/or supporting, the secondary structure when it approaches an overtravel position relative to the parent structure. It is also apparent that a connecting seal can act as a stabilizing and/or supporting connector.
Compared to a gyrostabilizer for a complete vehicle, the instant invention would utilize much smaller, lighter, faster responding, and less expensive gyrostabilizers since only the secondary structure need be stabilized by the gyrostabilizer. As an example of the magnitude of difference, consider that a fully loaded 102 by 34 foot Air Ride passenger ferry, including a fixed cabin with passengers, weighs approximately 140 long tons while, if separated as a secondary structure, the cabin including passengers weighs only about 40 long tons. Further, in the preferred embodiment of the present invention, a gyrostabilizer for the secondary structure is only working to stabilize a floating air supported cabin and not a boat hull that is subject to heavy force wave impacts. It is obvious that water presents much stronger impacts than air as it is approximately 800 times as dense. The terminology used to describe the preferred, air supported, version of the instant invention is Stabilized Air-Supported Structure which has the acronym SASS.
There is currently an attempt being made to develop a pitch and roll free ship's cabin by Mitsubishi Heavy Industries, Ltd. (MHI) of Japan. MHI's approach is to support the cabin with hull attached hydraulic actuators that are attached in series to shock absorbers where the shock absorbers are in turn attached to the supported cabin. Per an article from page 6 of the February 1988 issue of "Maritime Reporter and Engineering News" magazine, Editorial Offices, 118 East 25th Street, New York, N.Y. 10010, "A computer detects pitch and roll and dampens this by adjusting hydraulic cylinders, keeping the cabin level. The impact of motion is also absorbed by the shock-absorbing system." While MHI's approach is certainly workable, as demonstrated by a 481/2 foot demonstration hull that MHI has built, the instant invention provides significant advantages. Major disadvantages of the MHI system, compared to the instant invention, are that the MHI system requires support of all cabin weight and full cabin stabilization by the hydraulic cylinder and shock absorber connectors. The advantages of the instant invention are discussed in some detail in following sections.
There have been some patent activities that have at least some resemblance to the MHI system described in the "Maritime Engineering and Engineering News" magazine article. These include Tugwood, Great Britain Patent Specification 1,100,123, who describes a dampened spring mounted equipment carrier. Tugwood's is a device for protecting equipment from shock and vibration and cannot actively maintain a level carrier except by spring action so carrier orientation is dependent upon the orientation of the parent surface. That coupled with the fact that Tugwood has only anti-vibration spring and damper elements widely separate his patent from the instant invention. Liehmann, East German Patent 21,696, describes a hinged arm mechanism for maintaining a cabin-like structure. Liehmann has a similar limitation as the MHI concept in that all weight is supported by the arms rather than a large air cushion that floats the entire secondary structure as does the preferred embodiment of the instant invention. Further, Liehmann does not offer a gyroscope to orient the carrier by means of its precessional forces so his patent bears little resemblance to the instant invention.
Another concept is presented by Seiskusho, et al., Japan Patent 57-92441, who shows a suspended body that is supported by tensioned coiled threadlike support arms. The suspended body is positioned between parallel sides of a U-shaped fixed support frame structure. In Seiskusho's concept the supported body is always in essentially the same orientation in relation to the fixed support frame so supported structure orientation is not controllable, there is no supporting air cushion, and there is no gyrostabilizer in communication with the suspended structure; therefore, Seiskusho's invention has little resemblance to the instant invention.
Attempts at air supported structures include Sakamoto, U.S. Pat. No. 4,589,620, who shows a seat supported by a pneumatic cylinder and Karasawa; et al., U.S. Pat. No. 4,477,045, who shows a table that is supported by small air cylinders mounted on each corner of the table. While there two patents do present air cylinders as a means of support they do not offer the full size air support system of the preferred embodiment of the instant invention where the air support covers essentially the entire lower surface of the supported structure and therefore floats the supported structure on the air cushion. They also do not use gyroscope precessional forces to orient and stabilize the supported structure as is a part of the preferred embodiment of the instant invention. So, while there two patents do offer pressurized air support systems, they actually have little resemblance to the instant invention.
Matthews, U.S. Pat. No. 4,351,262, presents an unusual air cushion in a boat. He has a more or less standard catamaran hull form with a center wave following hull portion located between the catamaran sidehulls. Pressurized air is fed into the chamber between the upper and lower hull portions. Matthews does not offer stability beyond that of a standard catamaran hull, does not offer a stabilized air supported structure, and does not utilize a gyrostabilizer for any portion of his invention. Therefore, although he does show an air cushion under a boat hull, Matthews does not offer any of the valuable features of the instant invention.
Summers, U.S. Pat. No. 3,410,357, presents a gyro stabilized center-tracking motorcycle-like vehicle for travel over solid surfaces only. Summers offers a novel means to orient the gyro in the form of roadbed tracking wheels that return the gyro to its normal position in the event that it has been displaced. In any event, Summers does not employ a large pressurized air cushion for supporting and floating a secondary structure that is in turn gyrostabilized as in the case of the instant invention.
Gates, U.S. Pat. No. 3,731,543 and Acker, et al., U.S. Pat. No. 3,731,544, show rather complicated gyroscope based alignment systems. Gates is for a boresight alignment system for guns, rocket launch rails, and the like and Acker, et al. includes a star tracking system that uses the precise location of two known stars to update the position data in a gyroscopically based navigation system. While the control and operation of these two very complicated devices are based upon output data from gyroscopes they bear little resemblance to the instant invention. In the preferred embodiment of the instant invention, a secondary structure is supported primarily by a pressurized air cushion that has essentially the same support area as the lower surface of the supported structure, thus actually "floating" the supported structure, and the precessional forces of a powerful gyroscope are utilized to orient and stabilize the heavy supported structure, and the precessional forces of a powerful gyroscope are utilized to orient and stabilize the heavy supported structure that is, in its primary application, the passenger cabin in a boat or ship.
Variations of the present invention, other than the preferred embodiment which has a gas pressure supported and gyrostabilizer stabilized secondary structure, include: a gas pressure supported and connector stabilized secondary structure, a gyrostabilizer stabilized and connector supported secondary structure, and a secondary structure that is at least partially supported by a ball and socket, hinge, or other passive supporting system. Each variation can include portions of the others and can further include at least partial gas pressure stabilization for the secondary structure.